The invention discloses an intelligent diagnosis system for a power supply and a protection method. Mainly, a failure of the power supply system is judged by the following two manners: 1) judging whether the power supply system works normally by using an infrared signal spectrum and a sound spectrum, 2) finding all the potential failure modes through a failure model and impact analysis based on apower supply circuit model, performing simulation operation under all the failure modes and obtaining simulation data so that the simulation data is more targeted and representative; and constructingthe power supply failure model in a manner of training a chaotic neural network through the simulation data. The power supply failure information obtained through the two manners not only contains thepower supply failure type but also contains an integrated chip or an electronic element, which breaks down in the power supply circuit, thereby greatly facilitating the subsequent inspection and maintenance of the worker, reducing the workload, and improving the working efficiency.